Surveillance of Antibiotic Resistance in Gram-Negative Bacteria from Industrial Wastewater in Nairobi

Abstract

The environmental dispersal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) represents an increasing global public health concern. This challenge is especially pronounced in low and middle-income countries where industrial wastewater management remains inadequate. Industrial wastewater serves as a reservoir of antibiotic resistant microorganisms. These microorganisms facilitate the transfer of resistance traits within natural ecosystems and ultimately to human populations through direct contact, the food chain or through contaminated water sources. The present study examined the occurrence of antibiotic resistant bacteria in industrial wastewater in Nairobi County, Kenya and evaluated their sensitivity profiles to commonly used antibiotics. A total of 101 bacterial isolates were recovered from the samples including Klebsiella pneumoniae (37.6%), Escherichia coli (36.6%) and Pseudomonas aeruginosa. (25.7%). Antibiotic sensitivity profiles were determined using the disc diffusion method against ten commonly used antibiotics. High resistance was observed to ampicillin (88.1%), trimethoprim/ sulfamethoxazole (54.4%), and tetracycline (45.5%). Moderate resistance was observed to ceftriaxone (45.5%) and ciprofloxacin (22.7%) while the lowest resistance rates were recorded for levofloxacin (9.9%) and gentamicin (8.9%). Pseudomonas aeruginosa exhibited 100% resistance to both trimethoprim/sulfamethoxazole and tetracycline. Multidrug resistance being defined as resistance to more than three classes of antibiotics was notably high among Klebsiella pneumoniae (47.4%) and also Escherichia coli (29.7%). These findings are consistent with global reports that document perseverance of antibiotic resistant bacteria in aquatic environments exposed to industrial contamination. The high resistance levels detected especially with the frequently dispensed antibiotics, highlights the probable health risks posed by environmental exposure to untreated or partially treated industrial discharge. This study highlights the role of industrial wastewater as a significant reservoir of multidrug resistant bacteria and underscores the urgent need for policy action and better wastewater management as well as integration of antimicrobial stewardship into both public health and environmental policy frameworks.